US entrepreneur and politician, mayor of New York City from 2002. A life-long Democrat and social liberal, supporting abortion rights and same-sex marriages, he ran for mayor as a Republican, reportedly because the Democrat nomination was more keenly contested. As mayor, he banned smoking in bars and clubs in the city and launched a campaign against street vendors and to reform public education. He maintained high levels of public approval and in 2005 was re-elected mayor by a landslide margin of 20%. In June 2007, he left the Republican Party to become an independent and was re-elected mayor in 2009, after the city council overturned a two-term mayoral limit.
One of the USA's richest people, he heads a global media and financial-data empire and spent nearly US$70 million on his successful mayoral campaign. Crucial to his success in the 2001 election was endorsement from the popular outgoing Republican mayor, Rudolph Giuliani.
Bloomberg was born and raised in Medford, Massachusetts, a suburb of Boston. After completing a Masters in Business Administration (MBA) at Harvard University in 1966, he joined the Wall Street financial services firm Salomon Brothers and by 1972 had become a partner, being particularly involved in developing its financial information systems. He was ousted from Salomon Brothers in 1981, when it was taken over, but used his US$10 million partnership buy-out to set up his own firm, Bloomberg LP. This expanded rapidly to become one of the world's leading financial-data and media firms, with radio, television, Internet, and publishing operations. Bloomberg's fortune was estimated at US$11.5 billion (in 2007), and he donates around US$200 million a year to educational, medical, and cultural causes.